I. Field of the Invention
This invention relates to a method for preparing symmetrical azines as well as mixtures containing symmetrical and unsymmetrical azines.
II. Description of the Prior Art
Aldehydes are known to react with ammonia in a complex manner giving rise to various addition, condensation or polymerization products (see for example, The Chemistry of the Carbon-Nitrogen Bond, S. Patai, Interscience, London, 1970, page 67) or with hydrogen peroxide to form unstable peroxide products and to give rise, after reaction with ammonia and hydrogen peroxide, to peroxidic compounds (see for example, J. Chem. Soc. 1969, p. 2678).
Moreover, it is known that ammonia, a ketone and hydrogen peroxide react together to produce aminoperoxides (see for example, J. Chem. Soc. 1969, C, page 2663) and in the presence of such catalysts as tungstic or molybdic acid, to an oxime (see for example, J. Gen. Chem. (U.S.S.R.) 1960, 30, p. 1635), or in the presence of the ammonium salts or hydroxides of metals of Group Ia and IIa of the Periodic Table of the Elements, result in azines (see copending application Ser. No. 267,921, filed June 30, 1972.
Another method for preparing azines comprising the oxidation of ammonia in the presence of a ketone or aldehyde by means of an oxidizing medium of hydrogen peroxide and cyanogen or a nitrile is fully disclosed in commonly assigned copending U.S. application Ser. No. 152,413, filed June 11, 1971.
Another method for preparing azines comprises oxidizing a secondary alcohol in the liquid phase to form peroxide products of the auto-oxidation of the alcohol and subsequently reacting the peroxidic products with ammonia in the presence of cyanogen or a nitrile. This method is fully disclosed in commonly assigned pending U.S. application Ser. No. 230,038, filed Feb. 28, 1972. Still another method of preparing azines comprises reacting ammonia, hydrogen peroxide and carbonyl compounds in the presence of a carboxylic ester as disclosed in commonly assigned pending U.S. application Ser. No. 340,763 filed Mar. 13, 1973.